Method of removing carbon and carbonaceous matter



June 15, 1948. v BORSOFF 2,443,373

METHOD OF REMOVING CARBON AND CARBONACEOUS MATTER Filed Aug. 20, 1945 I l/ //x l IN VEN TOR V/C TO!? N. BORSOFF.

AT TORNE Y.

UNITED STATES PATENT OFFICE METHOD OF REMOVING CARBON AND CARBONACEOUS MATTER Victor N. Borsofl, Berkeley, C'alif.

Application August 20, 1943, Serial No. 499399 2 Claims. (Cl. 134-20) My invention relates to a method and means for removing carbon and carbonaceous matter from varying things, such as engine parts, refinery equipment, painted surfaces, stoves, tools, and the like.

For purposes of illustration and example, I will describe my invention in its particular application to the removal of carbonaceous deposits from parts of internal combustion engines. It is understood, of course, that my invention is useful in the removal of carbon and carbon compounds from many other objects, articles, structures, and the like, regardless of the cause of deposit of said carbonaceous matter.

Removal of carbonaceous matter from parts of internal combustion engines has been for many years, and is, a common and vexatious problem in engine maintenance. Although great strides have been taken in recent years in the development of special, highly stable compounded lubricants, improvements in petroleum fuels, and the designs of engines, carbonaceous deposits remain an ever present factor tending to decrease engine efiiciency.

Carbonaceous deposits form on almost all engine parts that come in contact with the lubricating oil, fuel, or exhaust gases, and vary considerably, depending on the Operating conditions. Roughly, the deposits can be divided into three general classes, namely: sludge, "varnish-like" deposits, and heavy carbon or coke. Analyses show the deposits consist mainly of reaction products of lubricant or fuel contaminated with dust, dirt, products of engine wear, and residue from compounds used in fuels or lubricating oils.

Sludgs, generally emulsions of oxidized oil and water mixed with carbon, dirt and other mineral material, are fairly easily removed by washing with liquid hydrocarbon solvents. The "varnishlike" and. carbon deposits are insoluble in the above mentioned solvents and their removal is usually accomplished only by scraping, wirebrushing, `and sand-blasting or soaking in chemical cleaning; solutions. All of the heretofore known methods of removing "varnish" and carbon deposits are unsatisfactory because of the time and labor necessarily expended in carrying them out, inaccessibility of surfaces sought to be cleaned, deterioration of the article being cleaned by the cleaning process employed, and other factors.

Essentially, my invention is a method of dissipating carbonaceous matter by means of ozone (03). I have found that carbon and carbonaceous deposits can be oxidized to carbon dioxide (CO2) when subjected to ozone, a powerful oxdizing agent.

Removal of carbon from combustion chambers by means of burning with oxygen (02) has proved unsatisfactory because of the high temperature necessary to start the reaction. For example, carbon in the form of carbon-black or graphite, will not react with pure oxygen except by raising the temperature to over 800 F. High temperatures caused by burning carbon with oxygen tend to injure the material being treated, as by metallic distortion. I have found that graphite or carbon-black will gradually oxidize to carbon dioxide (COz) at much lower temperatures when the atmosphere is rich in ozone (03). The reaction is quite rapid at temperatures not exceeding 500 F.

The object of my invention, generally, is to improve methods and means for removing carbon and carbon compounds from various objects. Further, it is an object of my invention to expedite and facilitate removal of carbon and carbonaceous deposits from objects without injuring the object sought to be cleaned.

Another object of my invention is to cause removal of carbon and carbonaceous deposits from objects having seemingly inaccessible surfaces needing cleansing.

Another object is to provide a simple, inexpensive, and effective method and apparatus for removing carbon and carbon compounds from objects sought to be cleaned.

Other objects and advantages of my invention will appear by reference to the following description and drawing hereto appended.

I have found that a preferred procedure for removing carbon and carbonaceous deposits from engine parts and the like is to first wash the thing to be cleaned, as an engine part, in a light hydrocarbon solvent in order to dissipate as much as possible of the oily and other soluble matter present; then dry the part; place the part in a closed chamber in which the part is preferably heated to a temperature of between 300 F. to 500 F.; then ozone is introduced into the chamber and the parts left in the heated ozonized atmosphere until oxidation of the carbon and/or carbon compound is complete.

It is understood that the temperature may be varied over a wide range dependent upon the nature of the thing being cleaned. I have found that a temperature of between 300 F. to 500 F. is an effective temperature for treating metallic parts of engines without in any way causing injury thereto.

I refer now to the drawing which is a vertical sectional view of an apparatus suitable for practicing my invention.

The drawing illustrates a closed housing forming a reaction chamber 2, insulated as at 3, and having a window 4 and an insulated cover 5 hinged at 6.

In the housing or reaction chamber is a screen or otherwise perforated work support member 'I carried on the inner walls of the said housing by lugs= or brackets 8 at about the vertical midpoint of the housing. A heating element such as hotplate 9 is disposed near the bottom of the housing. This heating element may be an electrical one, and it is best to avoid oxidation of the resistance element and other parts thereof by the ozone (03). With this in View, a plate extends across the interior of the chamber, which is of such a size as to block o ingress of ozone (03) below it, This plate may be heated by the resistance element llJ supplied by current through the leads ll, and thus forms a part of the electric heater.

I provide an ozone (O3) inlet Conduit !2 leading into the chamber and a gas outlet Conduit |3 leading from the chamber. The ozone (03) inlet conduit is connected to a Conventional ozonizer (not shown), such as a silent electric discharge type. Preferably, the ozone inlet is disposed so that it will discharge ozone (03) directly onto the work being processed. The outlet conduit is connected to an escape (not shown).

I have shown an electric incandescent lamp M disposed within the chamber 2 in order to illuminate the interior thereof so that an observer may have visual access to the parts bein treated through the window 4. A thermometer !5 is also illustrated in the drawing to provide an easy temperature reading for the operator and enable informed control of the heating unit.

The object sought to be processed may be placed on the perforate support member, heat applied thereto, and ozone (03) then introduced chamber.

oxidation results, carbon dioxide (CO2) is formed by the reaction and is discharge d through outlet Conduit !3.

Alternatively, the objects to be treated may be first heated and then placed into any type of container and then ozone (03) introduced thereinto, either with or without application of further heat treatment. It is preferable that the ozone (03) reach and contact the objects to be treated as soon as possible after emission into the reaction chamber. Due to the density of the ozone (03), it is generally preferred to introduce the ozone into the chamber at a point above the work being processed so that it will gravitate thereon instead of away therefrom. The term "reaction chamber is meant to include any place where the ozone (03) can act upon the carbon or carbonaceous matter; as ;for example, in cleaning refinery equipment the ozone (03) may be introduced into tanks, stills, or the like, to remove carbonaceous matter therefrom.

It is obvious that many modifications, if desired, may be employed in theapparatus herein described, such as means for imparting a circulatory motion to the atmosphere within the 4 chamber, valve means for controlling ingress of ozone (03) and egress of carbon dioxide (002), and many other variations in the work support, heating, lighting and thermal control means, as w'ell as the physical embodiment ,of the chamber' proper.

I have found, for example, that engine parts which have :been extremely fouled by carbonaceous deposits, can be completedly cleaned in ten (10) minutes where the concentrationof ozone was -one-fourth of one percent. Other engine partswhich had been used with different fuels and under difierent Operating conditions than those "above mentioned, took a longer period of time for complete cleaning. The cleaning time depends on the type and thickness of the carbonaceous deposit, and temperature and percentage of ozone (03) present in the reaction chamber. Sometimes a light dust-like mineral ash remains on the cleaned object which can be easily dissipated by wiping witha clean cloth and/or the'use of a current of air underpressure or thej' like. The source of the ash-like material is probably a residue of the compounding material used in certain lubricating oils or fuels.

I have found by test that various metals such as aluminu'n, bronze and cold rolled steel can be cleaned by means of my invention with no weight loss in any case. I have also found that piston'frings need not be removed from the the carbonaceous matter, and it is obvious that heat may be employed at different times or in different ways than as herein mentioned., For example, the atmosphere in the reaction chamber may be' heated prior to,` or after, and/or' concurrently with the introduction of ozone' and/orthe bbject to be processed.,

What I claim is: 1. The method of removing carbonaceous ma-` terial from the surfaces of an object which comprises continuously subjecting said' material 'to the action of an atmosphere containing at least. approximately by weight ozone for a period` of time suificient to oxidize said material at a temperature below the kindling temperature of said material and not exceeding approximately 500 F.

2. Thefmethod of removing carbonaceous material from an object which comprises maintaining the temperature of said object below the kindling temperature of said material and within the approxi nate range of 300-F. to 500 F., continuously subjecting said material to the action of an atmosphere containing at least approximately %i by weight of ozone and continuously'removing the products of the reaction between said material and said atmosphere from the vicinity of said object.

VICTOR N. BORSOFF.

. (References on following page) 2,448 ,87 8 5 6 REFERENCES c''m Number Name Date 1,982,4s4 Runge Nov. 27, 1934 The following references are of record in t e 2,313,730 Boesing Mar. 16, 1943 file of ths patent: OTHER REFERENCES TED 5 UNI STATES PATENTS Vosmaer: Ozonej page 10; D. Van Nostrand Number N Date Co., New York, 1916.

503555 f 1893 Smith: "Organic Chemistry," 1926 edition, 731955 Jacobl June 1903 published by the Century Co., New York, pages 1,081,950 Elle' Dec. 23, 1 13 10 423 and 424 1,901,803 Davis Mar. 14:, 1933 

